The Hall Research HR-16P is an RS-232 serial unit capable of
controlling any unit with a serial port with thirty-three
(33) user-programmable Command Strings. The HR-16P supports
16 discrete inputs that detect a DC voltage level or contact
closure. It senses either “low-to-high” and “high-to-low”
transitions of the discrete inputs as well as problem similar
commands out the serial port of the unit to the serial unit
(usually a projector but not limited to that). The commands
can either be any ASCII or non-ASCII data which has
programmable delays embedded in the string.